Temporal interactions and moon illumination effect on mammals in a tropical semievergreen forest of Manas National Park, Assam, India

Species interactions play a vital role in structuring mammalian communities by stimulating behavioral responses in varied niche dimensions that affect sympatric associations and predator-prey relationships. We determined temporal overlap and effects of the moon cycle on dominant and sub-dominant mammalian assemblages in Manas National Park, India. A total of 36 species were captured, with 24,865 independent records over 11,294 trap nights. We collected 1,130 photographs of five large- and medium-sized carnivores and 1,541 photographs of 12 small carnivores. Fifty-one percent of records were detected during diurnal period, followed by 38% in nocturnal phase, and 11% during twilight. Small carnivores such as Prionailurus bengalensis and Viverridae spp. were strictly nocturnal, whereas Martes flavigula and Herpestidae spp. were diurnal. Medium-sized carnivores were either nocturnal (Neofelis nebulosa) or diurnal (Cuon alpinus), whereas large-sized carnivores (Panthera tigris, Panthera pardus, and Ursus thibetanus) were cathemeral. A high degree of temporal overlap (>0.75) was found between most sympatric carnivores with distinct activity peaks, while a low overlap (<0.50) was observed between different body-sized carnivores. Viverrids' activity was negatively correlated (r = -0.44, p < 0.01) with lunar cycles, perhaps to increase foraging efficiency or as an anti-predator strategy. Large prey (mu = 133.23 degrees) and small prey (mu = 131.35 degrees) activity were high during brighter nights due to better visual detection in detecting or avoiding predators. Dominant species activity was least affected by the lunar cycle among forest-dependent mammals, whereas subdominant species activity was either lunarphobic or lunarphilic. The study demonstrates the use of passive camera traps in understanding the behavioral rhythms of tropical mammals.